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Posted Jul 18, 2012, 3:50 a.m. EDT Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.2a 5 Replies

Morales Dalmau
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hi,
I'm doing a simulation where I've mapped T in 2D (heating solids). After that I need Ray tracing module to focus a beam going through the heated material. The refraction index changes with T and I want to know how can I introduce that variable (with T) that I've plotted before.
1. Study of T.
2. Study of Ray tracing where n(T).

How can I do the second point?

tx,


jordi
5 Replies Last Post Jul 18, 2012, 10:41 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jul 18, 2012, 6:10 a.m. EDT
Hi

for the n(T) you need to define the material index of refraction as a lookup table or interpolated function related to T[1/K] take car to check carefully the normalisation, COMSOL operates by default in Kelvin, while many index of refraction formulas are related to deg C

you can perform a first analysis for T, and use the values of the first analysis as baseline for the second, for initial conditions as well as for "variables not solved for"

--
Good luck
Ivar
Hi for the n(T) you need to define the material index of refraction as a lookup table or interpolated function related to T[1/K] take car to check carefully the normalisation, COMSOL operates by default in Kelvin, while many index of refraction formulas are related to deg C you can perform a first analysis for T, and use the values of the first analysis as baseline for the second, for initial conditions as well as for "variables not solved for" -- Good luck Ivar
Morales Dalmau
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Posted: 1 decade ago Jul 18, 2012, 6:19 a.m. EDT
Great

Thanks for the info!!
Great Thanks for the info!!
Morales Dalmau
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Posted: 1 decade ago Jul 18, 2012, 8:14 a.m. EDT
It doesn't work... Have you got some-simple-models? they could be usefull, please.
The point is that I don't know how to create a link between n(T) and T because I have to create a new variable T (i don't know)l. Program says me that "unknown variable T", is there a specific name for temperature?

thanks
It doesn't work... Have you got some-simple-models? they could be usefull, please. The point is that I don't know how to create a link between n(T) and T because I have to create a new variable T (i don't know)l. Program says me that "unknown variable T", is there a specific name for temperature? thanks
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jul 18, 2012, 9:30 a.m. EDT
Hi

indeed by default if you have no HT there is no T defined. either its a constant then you add a Parameter T =293[K] or whatever value, or its a field (ie. T(x,y,z,t ...) ) in which case its easier to run a HT simulation first that defines the variable T (dependent variable of HT) and you refer to this T

--
Good luck
Ivar
Hi indeed by default if you have no HT there is no T defined. either its a constant then you add a Parameter T =293[K] or whatever value, or its a field (ie. T(x,y,z,t ...) ) in which case its easier to run a HT simulation first that defines the variable T (dependent variable of HT) and you refer to this T -- Good luck Ivar
Morales Dalmau
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Posted: 1 decade ago Jul 18, 2012, 10:41 a.m. EDT
Yes! thanks, the problem was not to define first the variable T! jaja

Jordi Morales-Dalmau
Yes! thanks, the problem was not to define first the variable T! jaja Jordi Morales-Dalmau

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